1. Field of the Invention
This invention relates to the construction of an electric furnace and more particularly to a novel apparatus and method for supporting electric heating elements in a furnace.
2. Technical Considerations
Many industrial processes that require high temperature environments use electric furnaces. Typical electric furnace design includes an outer structural casing with an internally insulated cavity. Electric heating elements are suspended from hangers within the furnace. When solid insulation, such as firebrick, can be used to insulate the furnace, the hangers are generally secured directly to the insulation. When a lightweight insulation is required, low inertia ceramic fiber insulation has been used. This insulation can be installed in module-type packages or in batts and attached to the furnace wall in a variety of ways, such as impaling the insulation over a stud or some other well-known technique. To support the electric heating elements, the hangers either penetrate the insulation and are secured to the outer casing, or the hangers are secured to short rods embedded within the insulation. When the hangers are directly secured to the furnace casing, the furnace walls can develop hotspots at these connections. In addition, when the short embedded anchor rods are used, it has been found that over a period of time, the weight of the rods and the supported electrical heating elements caused the fiber insulation to become packed, that is compressed. As a result, the relative positions of the hangers and electric heating elements can change within the furnace.
It would be advantageous to have an arrangement for lightweight furnace construction whereby the electric heating elements could be positioned within a furnace and maintained in their original position without affecting the insulating layers.